Sleep apnea syndrome is defined as a condition in which an apnea episode where cessation of breathing for ten seconds or longer occurs 30 times or more during seven hours of sleep or five times or more per hour of sleep. Sleep apnea syndrome causes symptoms such as uncontrollable daytime sleepiness, depression, impaired concentration, snoring, etc. Furthermore, since a patient with sleep apnea syndrome is asleep when apnea episodes occur, in many cases, finding of sleep apnea syndrome is delayed when the patient does not have any other person to live with, such as family members, etc.
In order to receive a complete examination of sleep apnea syndrome, hospitalization in a hospital having a rooms equipped with data monitoring devices for the examination and analysis of data thus monitored by a medical specialist are recommended. In other words, a patient not only has a burden of costs and time, but also has a physical burden since the patient is often asked to wear sensors on his/her body.
In view of the above, it is desirable to provide a method that allows an individual person to detect the presence or absence of an apnea episode during sleep simply at home, etc.
Simple methods for detecting an apnea episode during sleep may include, for example, a method disclosed in Japanese Laid-open Patent Publication No. 2001-029328 that records a sound during sleep and determines an occurrence of apnea episode when a state where the sound is equal to or less than a predetermined threshold continues for a certain period of time or longer. Furthermore, for example, International Publication Pamphlet No. WO 2011/010384 discloses a method that records a sound during sleep and detects an apnea episode based on a sudden sound uttered immediately after the apnea episode (for example, short breathing, groan).